Joshua, it's is always risky to give recommendations, but I have also learned much from [1] Myatt: Open Source Solutions - R. (a free brief introduction to using the R environment in Rich Text (.RTF) and Acrobat (PDF) formats and including sample data written by Mark Myatt <mark at myatt.demon.co.uk>, available at http://www.myatt.demon.co.uk/Rex1031.zip ) [2] P. Dalgaard: Introductory Statistics with R. Springer 2002. ISBN 0-387-95475-9 [3] J. Fox: An R and S-plus Companion to Applied Regression. Sage 2002. ISBN 0-7619-2280-6 Take a look and happy R'ing Wolfgang -- Wolfgang Lindner Lindner at math.uni-duisburg.de Gerhard-Mercator-Universitaet Duisburg Tel: +49 0203 379-1326